[Medical Q&A] If the mother is infected with hepatitis B virus, what is the risk of the baby being infected with hepatitis B virus?

Author: Hu Fang, deputy chief physician of Guangzhou Women and Children's Medical Center

Reviewer: Wang Qian, researcher at the Maternal and Child Health Center of the Chinese Center for Disease Control and Prevention

my country is a country with moderate prevalence of hepatitis B virus infection, with about 93 million people carrying the virus. Most of the infections are caused by early hepatitis B virus infection in babies, and mother-to-child transmission is the main route of hepatitis B virus infection. If the baby is not vaccinated with hepatitis B immunoglobulin and hepatitis B vaccine after birth, the baby born to a mother infected with hepatitis B virus (hereinafter referred to as "hepatitis B mother") will have a 30% to 42% chance of being infected with hepatitis B virus. If the baby is vaccinated with hepatitis B immunoglobulin and hepatitis B vaccine after birth, the probability of being infected with hepatitis B virus will drop to 5% to 15%.

In addition, after babies born to mothers with hepatitis B complete three doses of hepatitis B vaccine, the incidence of no/weak response to the hepatitis B vaccine is as high as 27.5% to 30.2%, which is much higher than that of babies born to mothers without hepatitis B (5% to 10%). The lack/weak response of babies to the hepatitis B vaccine increases their risk of hepatitis B virus infection in the future.

Therefore, blocking mother-to-child transmission is the key to controlling hepatitis B infection.